A closed reaction vessel at 400∘C contains a gaseous mixture for the synthesis of hydrogen chloride according to the balanced equation H2(g)+Cl2(g)⇌2HCl(g) The equilibrium constant for the reaction at 400∘C is Kc=3.5×103. The instantaneous, non-equilibrium molar concentrations in the vessel are [H2]=1.0×10−2M, [Cl2]=1.0×10−2M, and [HCl]=0.65M. No additional quantitative data are provided beyond the values above.
(a) Without performing a detailed numerical calculation, use reasoning based on the definition of Qc to predict whether the reaction mixture will experience a net formation of reactants or products as it approaches equilibrium. Explicitly reference the relative magnitudes of the numerator and denominator of the Qc expression in your explanation.
(b) Describe qualitatively how the molar concentrations of H2, Cl2, and HCl will change over time until equilibrium is re-established. Include particulate-level reasoning, that is, which species' molecules are consumed or generated, to support your answer.